Stator for electric rotary machine

ABSTRACT

A stator for an electric rotary machine includes: a stator core having a plurality of slots; and segmented coils of a plurality of phases, wherein: the segmented coils of a plurality of phases have pluralities of coil bars which are inserted individually in the plurality of slots in the stator core and which extend substantially in a straight line and pluralities of connection coils which connect together the coil bars of the same phase to thereby make up extending portions; and the coil bars are fixed in place individually in the slots in the stator core in such a state that the coil bars each are covered by an insulation material.

BACKGROUND

1. Field of the Invention

The present invention relates to a stator for an electric rotary machinewhich is installed in an electric vehicle or a hybrid vehicle and afabrication method of the same stator.

2. Description of the Related Art

Conventionally, there has been known a type of stators for electricrotary machines in which coils are fabricated by winding windings aroundteeth of a stator core. In addition, as another type of stators forelectric rotary machines, there have also been known stators in whichcoils are formed by inserting plural segments each made up of anelectric conductor which is formed into a U-shape using segment coils inslots in a stator core, and thereafter bending leg portions andconnecting end portions of the segments (refer to JP-A-2003-158840 andU.S. Pat. No. 6,894,417).

However, in such conventional electric rotary machines in which coilsare fabricated by winding windings around teeth of a stator core, thewindings and the stator core need to be handled separately. In addition,the winding operation becomes complex and troublesome since the windingsare wound while inserting insulation papers so as to be held between thewindings so wound, and there are caused fears that the insulation paperis caught between the winding wound, whereby a proper insulatingperformance cannot be ensured.

In addition, in the stators for electric rotary machines for vehiclesdescribed in JP-A-2003-158840 and U.S. Pat. No. 6,894,417, coils areformed through a forming operation of forming electric conductors into aU-shape, a bending operation of bending leg portions and a joining(welding) operation of joining together end portions of the electricconductors. Consequently, until the coils are formed through the joiningoperation, the stator core and the plural U-shaped electric conductorsneed to be handled separately. Further, since the U-shaped electricconductor is inserted in the slot after the insulation paper is insertedtherein, there are caused fears that the electric conductor comes intocontact with the insulation paper when the electric conductor is soinserted, and the insulation paper is caught between the electricconductor and the slot, whereby a proper insulating performance cannotbe ensured.

SUMMARY

The invention has been made in view of the problems described above, andan object thereof is to provide a stator for an electric rotary machinewhich is superior in handling properties of a stator core and coils andinsulation properties.

With a view to attaining the object, according to a first aspect of theinvention, there is provided a stator (for example, a stator 10 in anembodiment which will be described later) for an electric rotary machineincluding:

a stator core (for example, a stator core 21 in the embodiment) havingplural slots (for example, slots 23 in the embodiment); and

segmented coils of plural phases (for example, coils 50 in theembodiment), wherein

the segmented coils of plural phases have plural coil bars (for example,coil bars 25 in the embodiment) which are inserted individually in theplural slots in the stator core and which extend substantially in astraight line and plural connection coils (for example, connection coils40 in the embodiment) which connect together the coil bars of the samephase to thereby make up extending portions, and wherein

the coil bars are fixed in place individually in the slots in the statorcore in such a state that the coil bars each are covered by aninsulation material (for example, an insulation material 28 in theembodiment).

According to a second aspect of the invention, there is provided astator core for an electric rotary machine as set forth in the firstaspect, wherein

the coil bars of the same phase are inserted in the slot, and theinsulation material combines the coil bars in the slot so as to become awhole.

According to a third aspect of the invention, there is provided a statorcore for an electric rotary machine as set forth in the first or secondaspect, wherein

the coil bars which are inserted together in the slot have the samelength and are configured as a radially outer coil bar (for example, aradially outer coil bar 26 in the embodiment) and a radially inner coilbar (for example, a radially inner coil bar 27 in the embodiment) whichare aligned in a radial direction, and wherein

the radially outer coil bar and the radially inner coil bar are coveredby the insulation material in such a state that the radially outer andinner coil bars are offset from each other in an axial direction so thatend portions thereof take different axial positions.

According to a fourth aspect of the invention, there is provided astator core for an electric rotary machine as set forth in the thirdaspect, wherein

the radially outer coil bar and the radially inner coil bar which arecovered together by the insulation material are press fitted in the slotin the stator core.

According to the first aspect of the invention, the stator core, thecoil bars and the insulation materials are unitized since the coil barsare fixed in place individually in the slots in such a state that thecoil bars each are covered by the insulation material, whereby not onlyare the handling properties enhanced, but also the insulationperformance is enhanced. In addition, the coils of plural phases caneasily be fabricated by inserting the coil bars each covered by theinsulation material individually in the slots in the stator.

According to the second aspect of the invention, the handling propertiesare improved, and the plural coil bars as a whole can easily be insertedin the slot.

According to the third aspect of the invention, the coil bars can beconnected together in accordance with the axial positions of theconnection coils, and parts for the radially outer coil bar and theradially inner coil bar can be commonized.

According to the fourth aspect of the invention, the radially outer coilbar and the radially inner coil bar which are covered together by theinsulation material can be fixed in place in the slot in the stator coreeasily and in an ensured fashion.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingwhich is given by way of illustration only, and thus is not limitativeof the present invention and wherein:

FIG. 1 is a perspective view of a stator for an electric rotary machineaccording to the invention;

FIG. 2 is an exploded perspective view of the stator shown in FIG. 1;

FIG. 3A is an exploded perspective view of one of base plate assembliesshown in FIG. 2, and FIG. 3B is an exploded perspective view of theother base plate assembly;

FIG. 4 is a perspective view of a coil bar;

FIG. 5 is a vertical sectional view of the stator shown in FIG. 1 whichis taken along the line A-A in FIG. 6;

FIG. 6 is a front view of the one base plate assembly shown in FIG. 3A;

FIG. 7 is a rear view of the one base plate assembly shown in FIG. 3A;

FIG. 8 is a perspective view of double-slot type, segmented coils ofplural phases;

FIG. 9 is a perspective view of coils of one phase which are taken outfrom the coils of the plural phases shown in FIG. 8;

FIG. 10 is an exemplary diagram showing the configuration of the coilsof the plural phases;

FIG. 11A is a partial enlarged view of FIG. 6, and FIG. 11B is asectional view taken along the line B-B in FIG. 11A;

FIG. 12A is an exemplary diagram showing a state in which a coil bar andconnection coils are connected together through crimping, FIG. 12B is anexemplary diagram showing a state in which a coil bar havingsemi-spherical end portions is connected to connection coils throughpress fitting, and FIG. 12C is an exemplary diagram showing a state inwhich a coil bar having semi-circular end portions and a rectangularcross section is connected to connection coils by being press fitted inholes in the connection coils;

FIG. 13 is a perspective view of the stator in which cooling plates aredisposed on end faces of the base plate assemblies;

FIG. 14 is a vertical sectional view of a main part of the statorincluding the cooling plates shown in FIG. 13;

FIG. 15 is a perspective view of coils of one phase making upsingle-slot type coils of plural phases; and

FIG. 16 is a perspective view of coils of one phase making uptriple-slot type coils of plural phases.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment of the invention will be described byreference to the accompanying drawings. The drawings are to be seen inan orientation in which reference numerals given look properly.

As shown in FIGS. 1, 2 and 5, a stator 10 for an electric rotary machineaccording to this embodiment includes a stator core assembly 20 and apair of base plate assemblies 30L, 30R, and the base plate assemblies30L, 30R are disposed and assembled individually to ends of the statorcore assembly 20. An insulation sheet 65 which is made of, for example,silicone is disposed between the stator core assembly 20 and each of thebase plate assemblies 30L, 30R.

The stator core assembly 20 includes a stator core 21 and plural (48 inthe embodiment shown in the figures) coil bars 25.

The stator core 21 is made up, for example, of plural silicon steelsheets which are blanked out by a blanking press and are laminatedtogether and includes 48 teeth provided on a radially inner side thereofand 48 slots 23 which are formed between the teeth 22, 22 which lieadjacent to each other. The slots 23 are formed so as to penetrate thestator core 21 in an axial direction thereof and have a substantiallyelliptic shape which is elongated in a radial direction of the statorcore 21 when viewed from the axial direction thereof. The slots 23 alsohave opening portions 24 which are opened to an inner circumferentialsurface of the stator core 21.

Also referring to FIG. 4, the coil bar 25 includes a radially outer coilbar 26 and a radially inner coil bar 27 which have the same shape andlength. The radially outer coil bar 26 and the radially inner coil bar27 are disposed parallel while being offset from each other in the axialdirection by such an extent as a thickness of a connection coil 40,which will be described later. The radially outer coil bar 26 and theradially inner coil bar 27 are formed integrally by being covered on theperiphery thereof by an insulation material 28 which is injection moldedfrom a resin, with both ends of each coil bar left uncovered.Specifically, the length of each of the radially outer coil bar 26 andthe radially inner coil bar 27 is set to a length which is substantiallyequal to a sum of an axial length of the stator core 21 and a thicknessof three connection coils 40, and small-diameter portions 26 a, 27 a areformed at both the ends of the radially outer coil bar 26 and theradially inner coil bar 27, respectively, the length of thesmall-diameter portions 26 a, 27 b being substantially equal to thethickness of the connection coil 40.

The plural (48 in the embodiment shown in the figures) coil bars 25,each made up of the radially outer coil bar 26 and the radially innercoil bar 27, are, as shown in FIG. 5, aligned in a radial direction ofthe stator core 21 so that the radially outer coil bar 26 is situatedradially outwards and are inserted individually in the 48 slots 23 inthe stator core 21 to thereby be aligned in a circumferential directionof the stator core 21. Thus, the plural coil bars 25 make up the statorcore assembly 20.

The radially outer coil bars 26 are inserted individually in the slots23 so that the small-diameter portion 26 a projects approximately bysuch an extent as a thickness of two connection coils 40 from one endface 21 a (a left end face in FIG. 5) of the stator core 21, while thesmall-diameter portion 26 a projects approximately by such an extent asthe thickness of the connection coil 40 from the other end face 21 b (aright end face in FIG. 5).

Additionally, the radially inner coil bars 27 are inserted individuallyin the slots 23 so that the small-diameter portion 27 a projectsapproximately by such an extent as the thickness of the connection coil40 from the one end face 21 a of the stator core 21, while thesmall-diameter portion 27 a projects approximately by such an extent asthe thickness of two connection coils 40 from the other end face 21 b.The insulation material 28 that covers both coil bars 26 and 27 isinterposed between the radially outer coil bar 26 and the radially innercoil bar 27 and the slot 23 in the stator core 21 so as to ensure theinsulation between the radially outer and inner coil bars 26, 27 and thestator core 21. Consequently, the radially outer coil bar 26 and theradially inner coil bar 27 are covered by the insulation member 28 insuch a state that the radially outer and inner coil bars 26, 27 areoffset from each other in the axial direction so that the axialpositions of the end portions thereof differ from each other.

The insulation material 28 which covers the radially outer coil bar 26and the radially inner coil bar 27 has substantially the same shape asthat of the slot 23 and is sized slightly larger than the slot 23. Thus,the insulation material 28 can easily be press fitted in the slot 23 soas to be fixed in place therein. In addition, the radially outer coilbar 26 and the radially inner coil bar 27 are thicker than aconventional coil which is made up of a winding which is woundtherearound, and hence, there is provided an advantage that the spacefactor relative to the slot 23 is increased.

As shown in FIGS. 1 to 7, the base plate assemblies 30L, 30R which aredisposed individually at the ends of the stator core assembly 20 includebase plates 31L, 31R and plural connection coils 40. The base plateassembly 30R differs from the base plate assembly 30L in that the formerdoes not include a connecting terminal portion, which will be describedlater, and in that the shapes of grooves formed and the connection coilsprovided on the former differ from those of the latter. The otherconfigurations of both the base plate assemblies are the same, andtherefore, the base plate assembly 30L will mainly be describedhereinafter.

As shown in FIGS. 6 and 7, the base plate 31L is formed from a resin (anon-magnetic material) having insulating properties and is asubstantially annular member having substantially the same inside andoutside diameters as those of the stator core 21. A deployment portion31 a is provided at an upper portion of the base plate 31L as seen inthe figures so as to extend radially outwards therefrom into the shapeof a segment. A connecting terminal portion is formed on the deploymentportion 31 a for connection to external equipment or the like.

48 pairs of radially outer through holes 32 and radially inner throughholes 33 are formed to penetrate the base plate 31L at a radially innerside of the base plate 31L so as to correspond, respectively, to theradially outer coil bars 26 and the radially inner coil bars 27 of thecoil bars 25 which are inserted in the slots 23 in the stator core 21.

The radially outer through hole 32 and the radially inner through hole33 which make a pair are situated on the same straight line L whichextends from a center O of the base plate 31 in a radial direction.Further, a radially outermost hole 34 is formed on an outside diameterside of the base plate 31L. Thus, the radially outer and inner throughholes 32, 33 and radially outermost hole 34 establish a communicationbetween an outer surface 35 and an inner surface 36 of the base plate31L (refer to FIG. 5). Additionally, in a circumferential position wherethe deployment portion 31 a is formed, 12 connecting terminal joiningholes 39 are formed which are situated further radially outwards thanthe position of the radially outermost hole 34 in the deployment portion31 a.

As shown in FIGS. 5 to 7, plural (48) outer surface grooves 37 and innersurface grooves 38 are formed along involute curves so as to lie closeto one another on the outer surface 35 and the inner surface 36 of thebase plate 31L, respectively. The outer surface grooves 37 and the innersurface grooves 38 are formed to have a U-shaped section which is openedto the outer surface 35 and the inner surface 36, respectively. Theadjacent outer surface grooves 37 and the adjacent inner surface grooves38 are isolated by walls 31 b which is erected from the base plate 31L,and the outer surface groves 37 and the inner surface grooves 38 whichface each other in an axial direction are isolated by a bulkhead 31 c,whereby the outer surface grooves 37 and the inner surface grooves 38are electrically insulated one by one.

In addition, the base plate 31 is given an axial width which issubstantially equal to a sum of groove depths of the outer surfacegroove 37 and the inner surface groove 38 which correspond,respectively, to an outer connection coil 41 and an inner connectioncoil 42, which will both be described later, and a thickness of thebulkhead 31 c.

In the base plate assembly 30L, as shown in a front view of the baseplate in FIG. 6, each outer surface groove 37 on the base plate 31L isformed in a curved fashion along the involute curve so as to connect oneradially outer through hole 32 with one radially outermost hole 34 whichis formed on a straight line L which passes through a radially outerthrough hole 32 which lies three radially outer through holes ahead in aclockwise direction from the one radially outer through hole 32. In theplural outer surface grooves 37, however, 12 outer surface grooves 37 awhich extend towards the deployment portion 31 a extend in an involutefashion from the corresponding radially outer through holes 32 tostraight lines L which pass through the radially outer through holes 32which lie three radially outer through holes ahead in the clockwisedirection from the radially outer through holes 32 from which the outersurface grooves 37 a start to extend and thereafter are bent radiallyoutwards so as to connect to the corresponding connecting terminaljoining holes 39.

As shown in a front view of the base plate in FIG. 7, each inner surfacegroove 38 on the base plate 31 is formed in such a curved fashion as toavoid the interference with the corresponding radially outer throughhole 32 so as to connect one radially inner through hole 33 with oneradially outermost hole 34 which is formed on a straight line L whichpasses through a radially inner through hole 33 which lies threeradially inner through holes ahead in a clockwise direction (in acounterclockwise direction when seen from the front side of the baseplate 31L shown in FIG. 6) from the one radially inner through hole 33.In the plural inner surface grooves 38, however, 12 inner surfacegrooves 38 a which extend towards the deployment portion 31 a extendsimilarly in a curved fashion from the corresponding radially innerthrough holes 33 to straight lines L which pass through the radiallyinner through holes 33 which lie three radially inner through holesahead in the clockwise direction (in the counterclockwise direction whenseen from the front side of the base plate 31L shown in FIG. 6) from theradially inner through holes 33 from which the inner surface grooves 38a start to extend and thereafter are bent radially outwards so as toconnect to the corresponding connecting terminal joining holes 39.

Namely, as shown in FIG. 6, the radially outer through hole 32 and theradially inner through hole 33 which are spaced six radially outer orinner through holes apart from each other in the clockwise direction (orin the counterclockwise direction) are connected to each other via theradially outermost hole 34 to which the outer surface groove 37 and theinner surface groove 38 commonly connect. In addition, the pair of outersurface groove 37 a and inner surface groove 38 a which connect to thecommon connecting terminal joining hole 39 connect the radially outerthrough hole 32 with the radially inner through hole 33 which are spacedsix radially outer or inner through holes apart from each other in theclockwise direction (or in the counterclockwise direction).

In the base plate assembly 30R, each outer surface groove 37 on the baseplate 31R has the same shape of each inner surface groove 38 on the baseplate 31L, and each inner surface groove 38 on the base plate 31R hasthe same shape as each outer surface groove 37 on the base plate 31L.

The connection coil 40 is formed of a conductive material such as copperinto the shape of a plate. The connection coils 40 are divided intoouter connection coils 41 (41 a, 41 b) which are inserted in the outersurface grooves 37, 37 a and inner connection coils 42 (42 a, 42 b)which are inserted in the inner surface grooves 38, 38 a. When referredto herein, the outer connection coils 41 are the connection coils 40which are disposed on an axially outer side of the stator 10 when thestator core assembly 20 and the base plate assemblies 30 are assembledtogether, and the inner connection coils 42 are the connection coils 40which are disposed on an axially inner side of the stator 10.

As shown in FIG. 6, the outer connection coils 41 a are formed along theinvolute curves having the same shape of the outer surface grooves 37,and connection holes 43 a, 43 b are formed at both end portions of theouter connection coils 41 a. The connection hole 43 a has a diameterwhich is substantially the same as that of the small-diameter portion 26a of the radially outer coil bar 26, and the connection hole 43 b has adiameter which is substantially the same as that of a connecting pin 45,which will be described later, for connecting together the outerconnection coil 41 a and the inner connection coil 42 a. In addition,the outer connection coils 41 b are formed in a curved fashion to havethe same shape as that of the outer surface grooves 37 a, and connectionholes 43 a and connecting terminal holes 43 c are formed at both endportions of the outer connection coils 41 b.

As shown in FIG. 7, the inner connection coils 42 a are formed along theinvolute curves having the same shape of the inner surface grooves 38,and connection holes 44 a, 44 b are formed at both end portions of theinner connection coils 42 a. The connection hole 44 a has a diameterwhich is substantially the same as that of the small-diameter portion 27a of the radially inner coil bar 27, and the connection hole 44 b has adiameter which is substantially the same as that of the connecting pin45. In addition, the inner connection coils 42 b are formed in a curvedfashion to have the same shape as that of the inner surface grooves 38a, and connection holes 44 a and connecting terminal holes 44 c areformed at both end portions of the inner connection coils 42 b.

Consequently, except for the portion of the base plate 31L where theconnecting terminal joining holes 39, the inner connection coils 42 aand the outer connection coils 41 a, 41 b that are all connected to theradially outer coil bars 26 are formed along the involute curves, andthe inner connection coils 42 a, 42 b and the outer connection coils 41a that are all connected to the radially inner coil bars 27 are formedalong the involute curves so as to extend radially outwards from theradially inner through holes 33 on a radially inner side of the involutecurves with bypassing the radially outer through hole 32.

The outer connection coils 41 a, 41 b are inserted in the outer surfacegrooves 37, 37 a, respectively, and the inner connection coils 42 a, 42b are inserted in the inner surface grooves 38, 38 a, respectively. Theconductive connecting pins 45 which are made of copper or aluminum areinserted in the radially outermost holes 34 so as to electricallyconnect the outer connection coils 41 a and the inner connection coils42 a.

By so doing, the base plate assemblies 30L, 30R are built up in such astate that the connection holes 43 a of the outer connection coils 41 aand the connection holes 44 a of the inner connection 42 a which aredisposed six connection holes apart from each other in the clockwisedirection (or in the counterclockwise direction) are electricallyconnected via the outer connection coils 41 a, the connecting pins 45and the inner connection coils 42 a.

In place of providing the connecting pins 45 as in this embodiment, aconfiguration may be adopted in which projecting portions having thesame shape of the connecting pin 45 are formed integrally on either ofthe outer connection coils 41 a and the inner connection coils 42 a, sothat the projecting portions so formed are inserted in connection holes43 b, 44 b which are provided on the other of the outer connection coils41 a and the inner connection coils 42 a, whereby the outer connectioncoils 41 a and the inner connection coils 42 a are electricallyconnected to each other.

The pair of base plate assemblies 30L, 30R, which are configured as hasbeen described heretofore, are disposed in the predetermined positionson both the ends of the stator core assembly 20 so as to be assembledthereto. As shown in FIG. 5, in the base plate assembly 30L which isdisposed at the one end face 21 a (the left end face in the figure) ofthe stator core 21, the small-diameter portions 26 a of the radiallyouter coil bars 26 are inserted in the connection holes 43 a of theouter connection coils 41 a, 41 b, and the small-diameter portions 27 aof the radially inner coil bars 27 are inserted in the connection holes44 a of the inner connection coils 42 a, 42 b. Thereafter, thesmall-diameter portions 26 a, 27 a are crimped to be fixed in place inthe corresponding connection holes 43 a, 44 a. Namely, the outerconnection coils 41 a, 41 b and the inner connection coils 42 a, 42 bconnect together the coil bars 25 of the same phase (for example, aU-phase) to thereby form extending portions of a coil 50.

In the base plate assembly 30R which is disposed at the other end face21 b (the right end face in the figure) of the stator core 21, thesmall-diameter portions 26 a of the radially outer coil bars 26 areinserted in the connection holes 44 a of the inner connection coils 42a, and the small-diameter portions 27 a of the radially inner coil bars27 are inserted in the connection holes 43 a of the outer connectioncoils 41 a. Thereafter, the small-diameter portions 26 a, 27 a arecrimped to be fixed in place in the corresponding connection holes 43 a,44 a. Namely, the outer connection coils 41 a and the inner connectioncoils 42 a connect together the coil bars 25 of the same phase (forexample, the U-phase) to thereby form extending portions of the coil 50.

Consequently, with respect to the radially outer coil bar 26 and theradially inner coil bar 27 which are disposed in the same slot 23, theouter connection coil 41 a which is connected to the one end (the leftend in the figure) of the radially outer coil bar 26 extends radiallyoutwards and in the clockwise direction to connect to the innerconnection coil 42 a of the same phase, while the inner connection coil42 a which is connected to the other end (the right end in the figure)of the radially outer coil bar 26 extends radially outwards and in thecounterclockwise direction to connect to the outer connection coil 41 aof the same phase. In addition, the inner connection coil 42 a which isconnected to the one end (the left end in the figure) of the radiallyinner coil bar 27 extends radially outwards and in the counterclockwisedirection to connect to the outer connection coil 41 a of the samephase, while the outer connection coil 41 a which is connected to theother end (the right end in the figure) extends radially outwards and inthe clockwise direction to connect to the inner connection coil 42 a ofthe same phase.

In this way, the stator 10 is made up by assembling the pair of baseplate assemblies 30L, 30R to both the ends of the stator core assembly20, whereby segmented coils 50 make up four coil loops for each phasewhich has the same construction (U-phase coils 50U, V-phase coils 50V,and W-phase coils 50W). In these four coil loops of the three phases(the U-phase coils 50U, the V-phase coils 50V, and the W-phase coilsSOW), two coil loops make up a set, and hence, two sets of U-phase coils50U, two sets of V-phase coils 50V, and two sets of W-phase coils 50Ware wave wound in the counterclockwise direction in this order (refer toFIGS. 8 and 10). Then, the radially outer coil bar 26 and the radiallyinner coil bar 27 which are covered together by the insulation material28 to be disposed within the same slot 23 each include two coil loopswhich make up one set. FIG. 8 is a perspective view of double-slot type,segmented coils of plural phases (U-, V- and W-phase) which are takenout from the stator for better understanding, and FIG. 9 is aperspective view of coils of one phase (for example, U-phase) which aretaken out, in turn, from the coils of the plural phases. FIG. 10 is anexemplary diagram showing the configuration of the coils of the pluralphases, and in FIG. 11A is a partial enlarged view of FIG. 6, and FIG.11B is a sectional view taken along the line B-B in FIG. 11A.

Additionally, in the stator 10 which is configured in the way describedheretofore, the outer connection coils 41 a, 41 b and the innerconnection coils 42 a, 42 b are disposed within a region where thestator core 21 is projected in the axial direction and are disposed indifferent positions with respect to the axial direction.

In the sectional view of the base plate assembly 30L taken along theline B-B which is shown in FIG. 11A, as shown in FIG. 11B, on the outersurface of the base plate 31L, two V-phase outer connection coils 41 band one W-phase outer connection coil 41 b are aligned in this orderfrom in a radially inward to outward direction at the small-diameterportion 26 a of the U-phase radially outer coil bar 26 from a radiallyinner side, while on the inner surface of the base plate 31L, oneU-phase connection coil 42 b and two W-phase inner connection coils 42 bare aligned in this order from the radially inner. Consequently, as isclear from FIG. 11A, the inner connection coils 42 a, 42 b face theouter connection coils 41 a, 41 b of the different phase in the axialdirection, and the outer connection coils 41 a, 41 b face the innerconnection coils 42 a, 42 b of the different phase in the axialdirection.

In addition, outer surfaces of the plural outer connection coils 41 a,41 b which are disposed at the axially outer ends of the stator 10 arelevel with the end faces of the base plates 31L, 31R.

Additionally, as is shown in FIG. 5, the coils 50 are assembled to thestator 10 so that the outer connection coils 41 a, 41 b which connect tothe radially outer coil bars 26 are situated axially outwards at the oneend face 21 a of the stator core 21, while at the other end face 21 b ofthe stator core 21, the outer connection coils 41 a which connect to theradially inner coil bars 27 are situated axially outwards.

FIGS. 12A to 12C show conceptual diagrams showing connectingconstructions between a coil bar and connection coils. Hereinafter, theradially outward coil bar 26 is taken as an example for description.However, connecting constructions which will be described below can alsobe applied to the radially inner coil bar 27. In a radially outer coilbar 26 shown at FIG. 12A, tapered portions 26 b which are taperedtowards ends of the radially outer coil bar 26 are formed at both endportions, and a connection hole 43 a in an outer connection coil 41 a or41 b and a connection hole 44 a in an inner connection coil 42 a aremade into a tapered hole having a gradient which is substantially equalto that of the end portions of the radially outer coil bar 26. Theradially outer coil bar 26 and the connection coils 40 are assembledtogether so that the base plates 31L, 31R are assembled to the statorcore 21 and the connection coils 40 are then pressed axially relative tothe radially outer coil bar 26 by pressing members 61 of jigs by virtueof elastic forces of springs 69, whereby the connection holes 43 a, 44 aof the connection coils 40 are fitted on the tapered portions 26 b ofthe radially outer coil bar 26. Then, the end portions of the radiallyouter coil bar 26 are crimped by being crushed to be deformed at ends bya punch 62, whereby the coil bar 26 and the connection coils 40 arefixed together.

As this occurs, the fitting portions between the radially outer coil bar26 and the connection coils 40 are tapered, and therefore, even in casecenters of the radially outer coil bar 26 and the connection coils 40are offset slightly, the radially outer coil bar 26 and the connectioncoils 40 are centered by virtue of pressures applied thereto by thepressing members 61 so that the radially outer coil bar 26 and theconnection coils 40 are joined together at the tapered portions 26 b inan ensured fashion to thereby establish an electric communicationtherebetween. In addition, such joining can be executed at plurallocations (96 locations in this embodiment) through a single pressingoperation. Thus, the joining work can be executed efficiently, therebymaking it possible to increase the fabrication efficiency remarkably. Itshould be noted that the coil bar 25 and the connection coils 40 do notnecessarily have to be connected together by press fitting and crimping,and hence, they may be connected together by press fitting or crimping.Thus, a connection of the coil bar 25 and the connection coils 40 basedon press fitting will be described below.

End portions of a radially outer coil bar 26 shown in FIG. 12B areformed into a semi-spherical shape, and connection holes 43 a, 44 a ofconnection coils 40 are formed into a semi-spherical depressed portion.In this construction, the semi-spherical end portions of the radiallyouter coil bar 26 are press fitted in the connection holes 43 a, 44 a ofthe connection coils 40, whereby the radially outer coil bar 26 and theconnection coils 40 are joined together. In this construction, too, theradially outer coil 26 and the connection coils 40 can be centered. Inaddition, such joining can be executed at plural locations through asingle pressing operation, whereby the radially outer coil 26 and theconnection coils 40 can be joined together extremely efficiently.

A radially outer coil bar 26 shown in FIG. 12C is formed to have arectangular cross section, and end portions thereof are formed into asemicircular shape. In addition, connection holes 43 a, 44 a ofconnection coils 40 are similarly formed into a semicircular depressedportion, and the radially outer coil bar 26 and the connection coils 40are joined together by press fitting the end portions of the radiallyouter coil 26 into the connection holes 43 a, 44 a which are thesemicircular depressed portions. Being given the rectangular crosssection, the radially outer coil bar 26 of this embodiment has anangular shape which closely matches that of the slot 23, and therefore,the space factor of the slot 23 can also be enhanced.

FIG. 13 is a perspective view of the stator in which cooling plates aredisposed at end faces of the base plate assemblies, and FIG. 14 is avertical sectional view of a main part of the stator. As shown in FIGS.13 and 14, a pair of cooling plates 60 are disposed so as to be incontact with the base plate assemblies 30 which are provided at both theend faces of the stator 10. A refrigerant passageway 63 is formed in aninterior of the cooling plate 60 so that a refrigerant is allowed tocirculate therein. Then, a refrigerant which is sent under pressure froma refrigerant supply system, not shown, is circulated in, for example, adirection indicated by an arrow C (refer to FIG. 13) in the refrigerantpassageway 63 in the cooling plate 60. Thus, the stator 10 can be cooledpositively via the outer connection coils 41 a, 41 b (the extendingportions) of the stator 10 with which the pair of cooling plates 60 arein contact.

Additionally, side surfaces of the outer connection coils 41 a, 41 b areflat, and therefore, the outer connection coils 41 a, 41 b are broughtinto surface contact with the cooling plates 60. Because of this,compared with a conventional coil around which a winding is wound, thecontact area with the cooling plates 60, that is, the heat conductionarea is large, thereby making it possible to cool the stator 10efficiently.

Additionally, in the coils 50, at the one end face 21 a of the statorcore 21, the outer connection coils 41 a, 41 b which connect to theradially outer coil bars 26 are situated axially outwards, while at theother end face 21 b of the stator core 21, the outer connection coils 41a which connect to the radially inner coil bars 27 are situated axiallyoutwards. Therefore, the radially outer coil bars 26 and the radiallyinner coil bars 27 are cooled uniformly via the outer connection coils41 a, 41 b to thereby suppress the heat distribution of the coils.Further, the coils 50 are free from concerns caused when an oil coolingprocess using an ATF oil or the like is selected that the coils and theinsulation materials are badly affected by the ATF oil which is sprayedto the coils, the reliability and durability of the stator being therebyenhanced.

Thus, as has been described heretofore, the stator 10 according to theembodiment includes the stator core 21 and the segmented coils 50 ofplural phases, and the segmented coils 50 of plural phases have theplural coil bars 25 which are inserted individually in the plural slots23 in the stator core 21 and which extend substantially in the straightline and the plural connection coils 40 which connect together the coilbars 25 of the same phase to thereby make up the extending portions. Thecoil bars 25 are fixed in place individually in the slots 23 in thestator core 21 in such a state that the coil bars 25 each are covered bythe insulation material 28. Therefore, the stator core 21, the coil bars25 and the insulation materials 28 are unitized, whereby not only arethe handling properties enhanced, but also the insulation performance isenhanced. In addition, the coils 50 of plural phases can easily befabricated by inserting the coil bars 25 each covered by the insulationmaterial 26 individually in the slots 23 in the stator 21.

In addition, the coil bars 25 of the same phase are insertedindividually in the slots 23 in the stator core 21 while being combinedtogether by the insulation material 28 so as to become a whole, andtherefore, the handling properties are improved, and the plural coilbars 25 as a whole can easily be inserted in the slot 23.

Additionally, the coil bars 25 which are inserted together in the slot23 have the same length and are configured as the radially outer coilbar 26 and the radially inner coil bar 27 which are aligned in theradial direction, and the radially outer coil bar 26 and the radiallyinner coil bar 27 are covered by the insulation material 28 in such astate that the radially outer and inner coil bars are offset from eachother in the axial direction so that the end portions thereof take thedifferent axial positions. Therefore, parts for the radially outer coilbar 26 and the radially inner coil bar 27 can be commonized.

In addition, the radially outer coil bar 26 and the radially inner coilbar 27 which are covered together by the insulation material 28 arepress fitted in the slot 23 in the stator core 21, and therefore, theradially outer coil bar 26 and the radially inner coil bar 27 can befixed in place in the slot 23 in the stator core 21 easily and in anensured fashion.

It should be noted that the invention is not limited to the embodimentthat has been described heretofore and hence can be modified or improvedas required.

For example, in the embodiment, 12 connecting terminal joining holes 39are formed. However, the invention is not limited thereto, and hence, aconfiguration may be adopted in which six connecting terminal joiningholes 39 are formed, and adjacent connection coils of the same phase areconnected together.

Additionally, an insulation cover may be disposed at the axially outerends of the pair of base plate assemblies 30L, 30R. Alternatively, theaxially outer ends may be covered with a resin or the like.

The stator 10 of the invention is not limited to the double-slot typestator that has been described above. For example, the stator 10 can beconfigured as a single-slot type stator of which the shape of coils ofone phase is shown in FIG. 15 or can be configured as a triple-slot typestator of which the shape of coils of one phase is shown in FIG. 16. Ina three-phase, eight-pole, wave wound stator, in the case of thesingle-slot type stator, the number of slots in the stator core 21 is24, and in the case of the triple-slot type stator, the number of slotsin the stator core 21 is 72. The stator of either type has the sameconstruction as that of the double-slot type stator 10, and hence, thedescription thereof will be omitted here.

1. A stator for an electric rotary machine comprising: a stator corehaving a plurality of slots; and segmented coils of a plurality ofphases, wherein: the segmented coils of a plurality of phases havepluralities of coil bars which are inserted individually in theplurality of slots in the stator core and which extend substantially ina straight line and pluralities of connection coils which connecttogether the coil bars of the same phase to thereby make up extendingportions; and the coil bars are fixed in place individually in the slotsin the stator core in such a state that the coil bars each are coveredby an insulation material.
 2. The stator core for an electric rotarymachine according to claim 1, wherein the coil bars of the same phaseare inserted in the slot, and the insulation material combines the coilbars in the slot so as to become a whole.
 3. The stator core for anelectric rotary machine according to claim 1, wherein: the coil barswhich are inserted together in the slot have the same length and areconfigured as a radially outer coil bar and a radially inner coil barwhich are aligned in a radial direction; and the radially outer coil barand the radially inner coil bar are covered by the insulation materialin such a state that the radially outer and inner coil bars are offsetfrom each other in an axial direction so that end portions thereof takedifferent axial positions.
 4. The stator core for an electric rotarymachine according to claim 3, wherein the radially outer coil bar andthe radially inner coil bar which are covered together by the insulationmaterial are press fitted in the slot in the stator core.